Thanks @sipofwater ,
I read some Slim tutorial couple weeks ago, and still need sometime to get into the whole idea, generally on how API handle a request to database. I used to make a call to a database with a direct query inside the a php file which correspond directly with the page interface.
I will have a look on the github repo and I hope we can keep this conversation on this thread as I work on some slim tutorial 
Have a nice day!